I have two daughters ages 2 and 4. I'm not in med school yet, but I work full time. I just wanted to add that a home daycare can be an affordable alternative and can help to drastically minimize sick days.
The home daycare my girls go to costs about $300 less ($150 per child) a month than what I paid for a daycare center.
Also, when my girls were in a daycare center, they were sick ALL THE TIME! I was at the doctor's office every 2 weeks!!! I missed 14 days of work, which is a lot considering that I work as a school counselor (I have a lot of time off (summer, spring break, winter break, etc.).
Since being in the home daycare (August of this year) NEITHER of my little angels has been sick!!!!! This is a miracle for me.
I like the home daycare because it is like they are staying home with a "mom/grandma." My girls love the lady who watches them. She is like a family member to them.
Some home daycares are licensed and advertise, others are more like "babysitting" and are found via word of mouth. Some states require all home daycares to be licensed, others do not require licensure if a small number of children (less than 5 for example) are in the home. Licensure can drive up the price of the in-home daycare.
Good luck! Working or going to school with kids is tough! I think having kids forces you to manage your time more efficiently. I am not used to having any "down" time now that I am a mom.
Also, I love coming home from a rough day to see the smiling faces of my beautiful little girls!!! They fill me with such joy that I think anything is possible!!!!